Adaptive placement & chaining of virtual network functions with NFV-PEAR

Gustavo Miotto,Marcelo Caggiani Luizelli,Weverton Luis Da Costa Cordeiro,Luciano Paschoal Gaspary

doi:10.1186/s13174-019-0102-2

Abstract

The design of flexible and efficient mechanisms for proper placement and chaining of virtual network functions (VNFs) is key for the success of Network Function Virtualization (NFV). Most state-of-the-art solutions, however, consider fixed (and immutable) flow processing and bandwidth requirements when placing VNFs in the Network Points of Presence (N-PoPs). This limitation becomes critical in NFV-enabled networks having highly dynamic flow behavior, and in which flow processing requirements and available N-PoP resources change constantly. To bridge this gap, we present NFV-PEAR, a framework for adaptive VNF placement and chaining. In NFV-PEAR, network operators may periodically (re)arrange previously determined placement and chaining of VNFs, with the goal of maintaining acceptable end-to-end flow performance despite fluctuations of flow processing costs and requirements. In parallel, NFV-PEAR seeks to minimize network changes (e.g., reallocation of VNFs or network flows). The results obtained from an analytical and experimental evaluation provide evidence that NFV-PEAR has potential to deliver more stable operation of network services, while significantly reducing the number of network changes required to ensure end-to-end flow performance.

Highlights

1 Introduction Network Function Virtualization (NFV) is a relatively novel paradigm that aims at migrating functions like routing and caching, from proprietary appliances to software-centric solutions running on virtual machines
We extend our previous work by providing: (i) a more detailed discussion on the formal model to ensure the best provision of Service Function Chains (SFCs) in face of dynamic changes in demand and/or costs associated with networking equipment; (ii) an overview of the reference architecture and application programming interface fordesign and deployment of SFCs, agnostic of virtualization and infrastructure technologies; (iii) a description of a proof-of-concept prototypical implementation of NFV-PEAR; and (iv) a more detailed evaluation on the efficacy and effectiveness of NFV-PEAR
After presenting the Integer Linear Programming (ILP) model for adaptive placement and chaining of virtual network functions (VNFs), we introduce NFV-PEAR: an architecture for virtual network function deployment and orchestration3

Summary

Introduction

Network Function Virtualization (NFV) is a relatively novel paradigm that aims at migrating functions like routing and caching, from proprietary appliances (middleboxes) to software-centric solutions running on virtual machines. Instances of virtual network function m available Set of Service function chaining (SFC) requests to be deployed A single SFC request, composed of VNFs and their chainings SFC nodes (either a network function instance or an endpoint) Unidirectional links connecting SFC nodes Required physical location r of SFC endpoint i Distinct forwarding paths (subgraphs) contained in a given SFC q A possible subgraph (with two endpoints only) of SFC q VNFs that compose the SFC subgraph HqH,i Links that compose the SFC subgraph HqH,i Denotes whether there was a previous VNF placement Denotes whether there was a previous assignment of flow to VNF Denotes whether there was a previous flow chaining φ α, β, and γ CiP ∈ R+ BPi,j ∈ R+ DPi,j ∈ R+ CqS,i ∈ R+ BSq,i,j ∈ R+ DSq ∈ R+. 3.2 Model formulation The proposed model considers a multi-objective function, which simultaneously minimizes (i) resources consumed in the infrastructure (i.e., in N-PoPs, VNFs, and physical links), and (ii) (possible) changes in mappings due to fluctuation of allocated demand (e.g., provisioning of new VNFs, SFC reassignments, and VNF flow reassignments). By α, β, and γ , according to defined priorities

Objective:

Adaptive VNF placement and chaining with NFV-PEAR

Number of modifications required in the infrastructure